Ethanol content in plants of Brassica napus L. correlated with waterlogging tolerance index and regulated by lactate dehydrogenase and citrate synthase

Oilseed rape (Brassica napus L.) is susceptible to waterlogging stress. To study the role of some genes on waterlogging tolerance in B. napus, the ethanol content and expression levels of some key genes involved in both anaerobic and aerobic metabolism were studied in 12 cultivars of B. napus with different degrees of waterlogging tolerance. The waterlogging tolerance index (WTI) was significantly negatively correlated with the ethanol content and the transcript abundance of the lactate dehydrogenase (LDH) gene, and significantly positively correlated with transcript level of the citrate synthase (CTS) gene. WTI was not correlated with the transcript levels of genes encoding pyruvate decarboxylase (PDC), glyceraldehyde3 -phosphate dehydrogenase (GAPDH), or alcohol dehydrogenase (ADH). The correlation coefficient between WTI and ethanol content at 24 and 48 h after waterlogging treatments was 0.82 and 0.60, respectively. The correlation coefficient between WTI and the transcript level of BnCTS at 24 h and BnLDH at 48 h after waterlogging treatments was 0.74 and 0.73, respectively. These findings suggest that improving the 02 uptaking and transporting ability is important for increasing plant tolerance to waterlogging stress. Cultivars with strong waterlogging tolerance can be selected based on their ethanol content at 24 h after waterlogging treatment.